This thesis investigates how well the Alexandria (WBK) force-field can predict themelting point for multi-cation chloride salts with molecular dynamic (MD) simulationsin Gromacs 4.6.7. Researched is the eutectic ternary salt LiCl-NaCl-KCl(53.5-8.6-37.9 mol%) and its binary eutectic constituents(NaCl-LiCl: 22.5-77.5, KCl-NaCl: 50-50, LiCl-KCl: 58.5-41.5 mol%). The choosen salt mixtures are all promising candidates for use as electrolyte in liquidmetal batteries, a potential future power grid storage system. Simulation of the ternary salt's bulk at 298 K over 100 simulations with its ionsdifferently arranged within the crystal lattice for each simulation all resulted in stablecrystalline structures. This indicates that the WBK force-field properly andconsistently can produce stable crystalline structures not just for pure salts, but alsowithin multi-component ones. The melting point for the ternary and first binary combination was determined to550 K (12.9 % lower than experimental) and 950 K (12.6 % higher than experimental). No melting point could be determined for the last two binary combinations, as theymelted in their entire simulated temperature intervals. The ternary salt showcased acrystalline/amorphous mixture at solid phase temperatures when simulating with thesolid/liquid coexistence method. These simulation anomalies show that modeling ofmulti-cation chloride salts may not be as straight forward as it is with pure salts,despite using a force-field parameterized specifically for alkali halides.
| Identifer | oai:union.ndltd.org:UPSALLA1/oai:DiVA.org:uu-395271 |
| Date | January 2019 |
| Creators | Larsson Sihm, André |
| Source Sets | DiVA Archive at Upsalla University |
| Language | English |
| Detected Language | English |
| Type | Student thesis, info:eu-repo/semantics/bachelorThesis, text |
| Format | application/pdf |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | UPTEC ES, 1650-8300 ; 19 007 |
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